Surgical tool sterilizers use hot steam to sterilize surgical tools to decrease the likelihood of infections. The sterilizers comprise a housing wherein steam is injected after the tools have been inserted therein.
One problem with sterilizers is that use of steam will often result in water droplets appearing on the surgical tools. This is problematic as it may result in infections on patients operated with said tools and sometimes requires tools to be repeatedly sterilized before they are in an acceptable condition. In some cases where tools could not be sterilized properly, the operations on the patients even have to be cancelled entirely. One way to circumvent this problem is to provide steam in the sterilizers having a higher saturation level, or in other words wherein the steam quality or “dryness” will be higher. Sterilizers usually require to be provided with steam having a saturation level, also called the steam quality, of 97% or more, meaning that the liquid-state water micro-droplets carried by the steam will be 3% or less. This is likely to reduce risk of infections resulting from condensed water droplet formation on the surgical tools that originate from the injected steam. Control of steam saturation is normally accomplished at the boiler itself.
The challenge in controlling the saturation level of steam is twofold.
Firstly, the steam generated at the boiler for the sterilizer is conveyed through the large hospital building piping system. This allows the steam to loose energy during circulation through the pipes. So although the boiler may in fact generate steam with an appropriate quality, the steam that is outputted in the sterilizer might not be of adequate quality. Furthermore, the ambient parameters in the hospital might change over time, which can influence the steam quality. For example, the steam demand usually greatly varies at the hospital which requires the boiler to work at widely varying debit rates, resulting in varying steam quality over the entire hospital steam system including at the inlet of the sterilizer. Also, air or other non-condensable gases that will change the steam parameters and steam quality may be found in varying proportions from one hospital to the other within the steam pipes. So even if at one time the steam quality at the sterilizer is adequate, at another time the steam quality at the sterilizer might be inadequate for a same boiler due to circumstances identified above, among others.
Secondly, it is complex to measure the actual saturation level of steam. The present inventor is not aware of an efficient method of automatically measuring the saturation level at regular time intervals or, better yet, continuously. Manipulations need to be accomplished on the premises by an operator to first sample steam and then measure the saturation level in the sampled steam for example with a calorimeter, which is tedious and time-consuming. This is not an acceptable solution when steam saturation needs to be measured and controlled on a continuous basis since it would require a proficient operator to remain near the sterilizers for that purpose alone.